Pinpoint Test D: The Steering Wheel Control Illumination Is Inoperative

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

D1 CHECK THE OTHER DIMMABLE LIGHTING SWITCHES
- Ignition OFF.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Increase the backlighting brightness to the highest setting.
- Are all the dimmable switches inoperative?
- Yes: GO to PINPOINT TEST B .
- No: GO to D2.
D2 CHECK FOR VOLTAGE TO THE CLOCKSPRING
- Place the headlamp switch in the OFF position.
- Depower the Supplemental Restraint System (SRS). Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: Clockspring C218A.
- Connect: Negative Battery Cable.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Rotate the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the clockspring C218A-16, circuit VLN04 (VT/GY) (Fusion) or circuit VLN37 (BU/WH) (MKZ), harness side and ground.
  
  Fig 1: Checking Clockspring Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes: GO to D3.
- No: REPAIR circuit VLN04 (VT/GY) (Fusion) or circuit VLN37 (BU/WH) (MKZ). REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
D3 CHECK FOR VOLTAGE TO THE CLOCKSPRING USING THE CONNECTOR GROUND
- Measure the voltage between the clockspring C218A-16, circuit VLN04 (VT/GY) (Fusion) or circuit VLN37 (BU/WH) (MKZ), harness side and the clockspring C218A-7, circuit GD116 (BK/VT), harness side.
  
  Fig 2: Checking Voltage To Clockspring Using Connector Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes: GO to D4.
- No: REPAIR circuit GD116 (BK/VT) for an open. REPOWER the SRS. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
D4 CHECK THE CLOCKSPRING FOR AN OPEN
- Remove the driver air bag module. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: Upper Clockspring C218B.
- Measure the resistance between the clockspring C218a pin 16, component side and the upper clockspring C218b pin 7, component side.
  
  Fig 3: Measuring Resistance Between Clockspring C218A Pin 16 And Upper Clockspring C218B Pin 7, Component Side
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the clockspring C218a pin 7, component side and the upper clockspring C218b pin 2, component side.
  
  Fig 4: Measuring Resistance Between Clockspring C218a Pin 7 And Upper Clockspring C218b Pin 2
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes: GO to D5.
- No: INSTALL a new clockspring. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
D5 CHECK THE STEERING WHEEL HARNESS VOLTAGE CIRCUIT FOR AN OPEN
- Disconnect: Steering Wheel Switches C2997 and C2998.
- Measure the resistance between the upper clockspring C218B-7, circuit VLN04 (VT/GY), harness side and the LH steering wheel switch C2998-2, circuit VLN04 (VT/GY), harness side; and between the upper clockspring C218B-7, circuit VLN04 (VT/GY), harness side and the RH steering wheel switch C2997-1, circuit VLN04 (VT/GY), harness side.
  
  Fig 5: Checking Steering Wheel Harness Voltage Circuit For Open
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes: GO to D6.
- No: REPAIR or INSTALL a new steering wheel harness. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
D6 CHECK THE STEERING WHEEL HARNESS GROUND CIRCUIT FOR AN OPEN
- Measure the resistance between the LH steering wheel switch C2998-4, circuit GD165 (BK), harness side and the clockspring C218B-2, circuit GD165 (BK), harness side; and between the RH steering wheel switch C2997-3, circuit GD165 (BK), harness side and the clockspring C218B-2, circuit GD165 (BK), harness side.
  
  Fig 6: Checking Steering Wheel Harness Ground Circuit For Open
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes: INSTALL new steering wheel controls as necessary. REFER to CRUISE CONTROL or INFORMATION AND ENTERTAINMENT SYSTEMS . TEST the system for normal operation.
- No: REPAIR or INSTALL a new steering wheel harness. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.